Functional analysis of glucose-dependent insulinotropic polypeptide fusion proteins

Research output: Contribution to journalArticlepeer-review

Abstract

To generate functional fluorescently tagged glucose-dependent insulinotropic polypeptide (GIP), a series of GIP expression constructs were devised. These included G1 (complete preprohormone), G2 (lacking the C-terminal extension), G3 (lacking both N- and C-terminal extensions), G4 (G2 fused to green fluorescent protein, GFP), and G5 (G3 fused to GFP). Expression of G5 in bacteria generated immunopositive GIP together with GFP fluorescence, while G4 generated only fluorescence without immunoreactivity. Transfection of NIH3T3 cells with cDNAs of G1, G3, G5, but not G2, G4, and EGFP, resulted in immunologically detectable GIP formation, although fluorescence could be detected in the latter two. GIP as well as GIP-GFP secreted by NIH3T3 cells significantly stimulated intracellular cAMP accumulation and Ca2+ mobilization in SaOS2 cells. The GIP receptor antagonist GIP(7-30) abolished these responses. These results suggest that a GIP-GFP fusion protein seven times larger than the native peptide retains function and may be used as an in vivo probe to detect GIP receptor distribution and to explore GIP's biological roles.

Original languageEnglish (US)
Pages (from-to)575-582
Number of pages8
JournalPeptides
Volume22
Issue number4
DOIs
StatePublished - 2001

Keywords

  • Fusion protein
  • Glucose-dependent insulinotropic polypeptide (GIP)
  • Green fluorescent protein (GFP)
  • Peptide secretion
  • Signal transduction

ASJC Scopus subject areas

  • Biochemistry
  • Physiology
  • Endocrinology
  • Cellular and Molecular Neuroscience

Fingerprint

Dive into the research topics of 'Functional analysis of glucose-dependent insulinotropic polypeptide fusion proteins'. Together they form a unique fingerprint.

Cite this